A known image forming apparatus, e.g., a printer and a copier, includes a sheet feed tray, an ejection tray, and an image forming device disposed in a conveying path extending from the sheet feed tray to the ejection tray. The image forming device forms an image on a sheet being conveyed from the sheet feed tray toward the ejection tray.
A roller unit is disposed above the sheet feed tray. The roller unit includes a feed roller (or a pickup roller), a separation roller, and a frame holding the feed roller and the separation roller rotatably. The frame is connected to a pivotable arm. When the arm pivots, the roller unit pivots about an axis aligned with a rotation axis of the separation roller. Pivoting of the roller unit allows the feed roller to move vertically between a first position and a second position, which is higher than the first position.
Before a sheet is fed, the feed roller is located at the second position and a leading end portion of a sheet supported on the sheet feed tray is located under the feed roller. When the sheet is fed, the feed roller and the separation roller start to rotate. When the feed roller and the separation roller rotate, the arm pivots to allow the roller unit to pivot. When the roller unit pivots, the feed roller lowers from the second position to the first position and then returns from the first position to the second position. In lowering from the second position to the first position, the feed roller, which is rotating, is pressed against the sheet on the sheet feed tray, so that the sheet is fed from the sheet feed tray toward the conveying path.